In U.S. Pat. No. 3,908,657, a small, wearable medical pump for fluids is disclosed. Also, wearable pumps which comprise a pressure member adapted for orbital motion about an axis of rotation to pump liquids through flexible tubing are commercially available, and may be worn for either the withdrawal of blood for medical purposes or for the controlled infusion of critical medications which should be administered in very low but constant concentrations on an all-day basis. Accordingly, the patient is able to engage in his normal activities while wearing such a pump.
Such a pump is manufactured by Cormed, Inc. of Middleport, N.Y. The pressure member adapted for orbital motion is surrounded by a rigid sleeve, which defines an annular groove in its end. The tubing for pumping is forced into the end groove for operation of the pump.
This, however, provides a substantial disadvantage in that the tubing is difficult to get into the groove and into engagement with the pump head or pressure member without being pushed in by a pointed instrument of some kind. This, in turn, can damage the tubing if not done carefully.
Also, the above-cited miniature pump defines a single side slot, into which the tubing enters and exits from the rigid sleeve which surrounds the pump head. At those times, when the pump head is positioned against the side slot, it is possible for liquids to flow through the tubing in an uncontrolled manner, since the side slot provides a position for the tubing sections to retreat from the pump head, and thereby not be closed by the head as in the normal mode of operation. Particularly, if by chance the pump head is stopped in a position against the slot, flow can take place in a free and uncontrolled manner through the tubing, which is most undesirable, particularly when a critical dosage of medicament is being administered.
In the Olson U.S. patent application Ser. No. 104,407, filed Dec. 17, 1979 and entitled "Miniature Infusion Pump", improvements to the above-described structure are disclosed. The orbitally movable pressure member is surrounded by a sleeve member which is defined by a pair of substantially semi-circular jaws, attached together at one end in hinged relation for ease of installation.
In accordance with this invention, further improvements are provided in an orbital motion tubing pump for ease of use. Particularly, the number of detachable parts is reduced at the pump head, to avoid accidental loss of a detachable part. Also, the loading of pump tubing connected to a bag filled with medicament is easier by the improvements of this invention, and additional features for convenience and improved safety are provided.